In general, a mechanism such as a gearbox, a chemical pump, a stirrer, a mixer, a reactor, a transmission, a drier, or a compressor includes a drive shaft, and a rotary sealing device is installed on the drive shaft to prevent a leakage along the drive shaft.
The rotary sealing device includes a lip seal type sealing device, a mechanical seal type sealing device, and a radial shaft seal type sealing device based on types of sealing members.
For example, Korean Registered Patent No. 10-0356502, entitled “A Sealing Devices for Axis of Rotation Material”, published on Aug. 17, 2001, discloses a lip seal type rotary sealing device, and Korean Patent Application Publication No. 10-2006-0097034, entitled “Mechanical Seal Apparatus Utilizing Mechanical Seal”, published on Sep. 13, 2006, discloses a mechanical seal type rotary sealing device.
Typically, a mechanical seal type rotary sealing device is applicable to an extreme environment and has a great safety and an excellent sealing performance. However, the mechanical seal type rotary sealing device has a complex structure, has difficulties in maintenance, includes a number of components, and requires a great manufacturing cost.
Conversely, a lip seal type rotary sealing device is simply structured, is easily maintained, and requires a low manufacturing cost. However, when compared to the mechanical seal type sealing device, the lip seal type rotary sealing device has a low durability, a low sealing performance, and a low safety, and thus is applicable to a narrower field. Recently, a material and a structure of a lip seal type sealing member have improved, and the lip seal type rotary sealing device is applicable to an increasing number of fields.
In particular, in the field in which a rotary sealing device is used, a leakage accident leads to serious casualties and damage of property. Thus, it is significantly important to quickly and accurately detect whether the rotary sealing device is leaking, and to determine a time to replace the rotary sealing device.